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Abstract:

This invention reveals to the public the centralized sump oil and acid
oil treatment process and system. The process consist of (1) the filter;
(2) entry to reaction kettle, the sodium carbonate solution added at the
time of air floatation till PH value keeps about 6.0-8.0; and emulsion
splitter and flocculating agent added for further reaction; (3)
suspension of air floatation and static settlement; (4) the international
crude oil is collected after the detergent oil at the upper level of the
reaction kettle is dehydrated under normal and reduced pressure; the
wastewater is drained after filtering by the natural oil removal tank and
the oil-water filter; the sludge is solidified by the cement and the
quick lime and aluminium oxide are used as the coagulant aid for
solidifying the sludge. The centralized treatment process of sump oil and
acid oil not only greatly lowers the pollution of surroundings of the
oilfield and corrosion of equipment, but also changes waste into
valuable, reuses a great amount of crude oil and improves the economic
benefits of the oilfield. The sludge solidified can be directly used for
buildings.

Claims:

1. A kind of centralized treatment process of sump oil and acid oil is
characterized by: Step (1): filter the sump oil by a coarse filter for
removing coarse impurities to obtain filtered sump oil; Step (2): input
the filtered sump oil to the reaction kettle; compressed air is
introduced from a coil at bottom of the reaction kettle with a pore
diameter of 60-110 μm and it is stirred after tiny bubbles are
produced; at the same time, a sodium carbonate solution with a weight
percentage of 7-18% is added to the filtered sump oil till PH value of
the filtered sump oil keeps about 6.0-8.0; then an emulsion splitter with
a volume ratio of 0.4-0.8% is added to the filtered sump oil in the
reaction kettle; then a flocculating agent with a volume ratio of
0.1-0.5% is added in the filtered sump oil in the reaction kettle for
further reaction; the compressed air is provided for 2.5-3.5 hours; Step
(3): the compressed air is suspended and it is settled for 4-6 hours;
Step (4): provide detergent oil at upper level of the reaction kettle to
a purification tank, the detergent oil in the said purification tank is
filtered by a fine-mesh filter at a mesh diameter of 1-1000 μm; then
it is heated to 110-120.degree. C. and it is dehydrated in a dehydrating
tower under common pressure, then it is heated to 70-90.degree. C. by a
heat exchanger; then it is delivered to the dehydrating tower under a
reduced pressure for dehydration under 20-70 kPa to obtain national crude
oil; sewage produced after condensation of water vapor dehydrated by the
dehydrating tower under normal and reduced pressure and intermediate
sewage are delivered to a sewage tank; the sewage in the sewage tank is
delivered to a vertical natural oil removal tank to separate the oil and
water by way of gravity at a flow speed of 0.5-0.8 mm/s; a water outlet
is drained after filtering by a oil-water filter; oil sludge at upper
level is retained in the reaction kettle, and oil sludge in the reaction
kettle is rinsed with a sodium hydroxide solution at a temperature of
65-75.degree. C. and a weight percentage concentration of 10-20% at a
proportion of (1.5-2.5):1 for 15-25 min, and settled for above 2.5 hours;
detergent oil after washing with hot water at upper level is delivered to
the purification tank and intermediate soda solution is collected in a
soda solution tank, and sediment impurities at bottom of the reaction
kettle are delivered to a sludge solidifying tank with a sludge pump.

2. The said centralized treatment process of sump oil and acid oil
contained as per claim 1 is characterized by: the filtered sump oil
filtered by the coarse filter to remove the coarse impurities is
delivered to the reaction kettle via an oil pump, and the filtered sump
oil in the reaction keeps heats to the temperature of 55-70.degree. C.
and the said sodium carbonate solution is added in the filtered sump oil
so that PH value of the filtered sump oil maintains at 6.0-8.0, then
temperature of the filtered sump oil in the reaction kettle increases to
70-90.degree. C., and then the said emulsion splitter and the said
flocculating agent are added.

3. The centralized treatment process as per claim 1 or 2 is characterized
by: the said emulsion splitter is a non-ionic surface active agent with a
trunk chain of polyether, with terminal base containing hydroxide
radical, amino group, ether group and carboxyl; the said flocculating
agent has a main composition of polymerized alumina.

4. The centralized treatment process as per claim 1 is characterized by:
the said sodium carbonate solution is delivered to the reaction kettle by
a stainless steel magnetic pump for delivery of sodium carbonate
solution.

5. The centralized treatment process of sump oil and acid oil as per
claim 1 is characterized by: the said fine filter is made by a bag-type
fine-mesh filter with a filter precision of 1-1000 μm.

6. The centralized treatment process of sump oil and acid oil as per
claim 1 is characterized by: the said oil-water filter consists of a
coarse filter tank puddler for coagulation, separation and removal of
oil, a levitated sphere maze for removal of turbid by microvortex, an
annular space for removal of dregs and a walnut shell medium for filter
and purification.

7. The centralized treatment process of sump oil and acid oil as per
claim 1 is characterized by: the said sludge solidifying tank takes
weight of the sludge as reference, and 6-9% of Portland cement, 2-5% of
quicklime and 0.5-2% of alumina are added for the purpose of solidifying
the sludge after mechanical stirring.

8. A kind of centralized treatment system of sump oil and acid oil is
characterized by: it consists of a coarse filter for removal of coarse
impurities, an oil pump and a reaction kettle for delivery of sump oil, a
stainless steel magnetic pump for delivery of acid or alkali solution, a
purification tank, a sewage tank, a bag-type fine-mesh filter with a
precision of 1-1000 μm, a dehydration system under normal and reduced
pressure, a vertical natural oil removal tank for coagulation, separation
and removal of oil, a levitated sphere maze for removal of turbid by
microvortex, an annular space for removal of dregs and a walnut shell
medium for filter and purification.

Description:

[0002] With an in-depth awareness of the people who have been faced with
more and more serious environmental pollution in the world, the cleaning
and treatment of sump oil and acid oil of the oilfield attract more and
more attentions. The oilfield exploitation brings a great amount of sump
oil and acid oil which are difficult to dewater. Such non-standard oil
containing water, impurity and high viscosity was sold to the local
firing enterprises and refineries at a lower price in the past as the
firing oil and non-standard oil. Considering that it is not decomposed
and treated, such sump oil and acid oil contain a great amount of harmful
chemical compositions and it brings serious pollution and damage to the
surroundings of the oilfield and the production equipment. Additionally,
the penetrating sour gas volatilized by the acid oil pollutes the air of
surroundings. Such odor can be smelled a few kilometers away and it
seriously damage the physical health of employees in the oilfield. The
acid liquor causes the corrosion to the mechanical equipment. The coils
in the oil storage tank and the suction pumps are replaced regularly. In
this way, it greatly increases the production cost.

[0003] The acid liquor-contained sump oil has strong corrosion, and it
easily reacts with the colloid and asphaltine to form the particles in
suspension. It hinders the settlement and the alkali cannot be
neutralized so that it is difficult to separate the oil and water. Thus,
it is a difficult problem for many oilfield experts, for that the
acid-contained sump oil has great viscosity and proportion. A large
amount of acid water cannot be separated only by the way of settlement.
The simple treatment process has no effects on the viscosity and acid oil
in the sludge and it has no effects on purification. Therefore, the ideal
treatment approach is required for treatment and recovery.

[0004] Although there are many patent applications in treating oil sludge
and sump oil, for example, the patent application of 200510045971.9,
200710064407.0, 200610046997.x and 200710011114.6 is published with the
treatment methods of heavy oil sludge, tank cleaning oil sludge, sewage
and crude oil dehydration, yet the proper measures against the sump oil
and acid oil are not developed. It also does not encounter the difficulty
of oil, water and impurities in the sump oil and acid oil.

BRIEF SUMMARY OF THE INVENTION

[0005] In order to solve the recovery treatment difficulty of the sump oil
and acid oil, the main purpose of this invention is to provide one
effective treatment process of sump oil and acid oil to easily separate
the oil, water and impurity in the sump oil and acid oil. Meanwhile, this
process simple with low treatment cost.

[0006] This invention provides a specialized treatment system in the said
way.

[0007] The centralized treatment process of sump oil and acid oil,
consists of that (1) the sump oil is filtered by the coarse filter for
removing the coarse impurities; (2) enters to the reaction kettle; the
compressed air is introduced from the coil at the bottom of the reaction
kettle with the pore diameter of 60-110 μm and it is stirred after the
tiny bubbles are produced; at the same time, the sodium carbonate
solution with the weight percentage of 7-18% is added to the sump oil
till the PH value of the sump oil keeps about 6.0-8.0; then the emulsion
splitter with the volume ratio of 0.4-0.8% is added to the sump oil in
the kettle; then the flocculating agent with the volume ratio of 0.1-0.5%
is added in the sump oil in the kettle for further reaction. The
compressed air is provided for 2.5-3.5 hours; (3) the compressed air is
suspended and it is settled for 4-6 hours; (4) the detergent oil at the
upper level of the reaction kettle is provided to the purification tank,
the detergent oil in the said purification tank is filtered by the
fine-mesh filter at the mesh diameter of 1-1000 μm; then it is heated
to 110-120° C. and it is dehydrated in the dehydrating tower under
common pressure, then it is heated to 70-90° C. by the heat
exchanger; then it is delivered to the dehydrating tower under the
reduced pressure for dehydration under 20-70 kPa to obtain the national
crude oil; the sewage produced after condensation of the water vapor
dehydrated by the dehydrating tower under normal and reduced pressure and
the intermediate sewage are delivered to the sewage tank. The sewage in
the sewage tank is delivered to the vertical natural oil removal tank to
separate the oil and water by way of gravity at a flow speed of 0.5-0.8
mm/s. The water outlet is drained after filtering by the oil-water
filter; the oil sludge at the upper level is retained in the reaction
kettle, and the oil sludge in the reaction kettle is rinsed with the
sodium hydroxide solution at a temperature of 65-75° C. and the
weight percentage concentration of 10-20% at a proportion of (1.5-2.5):1
for 15-25 min, and settled for above 2.5 hours. The detergent oil after
washing with hot water at the upper level is delivered to the
purification tank and the intermediate soda solution is collected in the
soda solution tank, and the sediment impurities at the bottom of the
reaction kettle are delivered to the sludge solidifying tank with the
sludge pump.

[0008] The acid oil in this invention refers to the acid-contained sump
oil.

[0009] In this invention, the soda liquor is added when the fine air
bubbles and air suspension are made. After full reaction, the
demulsifying agent and flocculating agent are added to successfully break
the suspended particles in the oil sludge and easily settle and separate
the oil and water. In addition, the process is simple with low cost.

[0010] Further, the sump oil filtered by the coarse filter to remove the
coarse impurities is delivered to the reaction kettle after the oil pump,
and the sump oil in the reaction keeps heats to the temperature of
55-70° C. and the said sodium carbonate solution is added in the
sump oil so that PH value of the sump oil maintains 6.0-8.0, then the
temperature of the sump oil in the kettle increases to 70-90° C.,
and then the said emulsion splitter and the said flocculating agent are
added.

[0011] Further, the said emulsion splitter is the non-ionic surface active
agent with the trunk chain of polyether, with the terminal base
containing hydroxide radical, amino group, ether group and carboxyl. The
said flocculating agent has the main composition of polymerized alumina.

[0012] Further, the said sodium carbonate solution is delivered to the
reaction kettle by the stainless steel magnetic pump for delivery of
sodium carbonate solution.

[0013] Further, the said fine filter is made by the bag-type fine-mesh
filter with the filter precision of 1-1000 μm.

[0014] Further, the said oil-water filter consists of the coarse filter
tank puddler for coagulation, separation and removal of oil, levitated
sphere maze for removal of turbid by microvortex, annular space for
removal of dregs and the walnut shell medium for filter and purification.

[0015] Further, the said sludge solidifying tank takes the weight of the
sludge as the reference, and 6-9% of Portland cement, 2-5% of quicklime
and 0.5-2% of alumina are added for the purpose of solidifying the sludge
after mechanical stirring.

[0016] One central treatment system of sump oil and acid oil, wherein, it
consists of the coarse filter for removal of coarse impurities, the oil
pump and the reaction kettle for delivery of sump oil, the stainless
steel magnetic pump for delivery of acid or alkali solution, purification
tank, sewage tank, the bag-type fine-mesh filter with the precision of
1-1000 μm, the dehydration system under normal and reduced pressure,
the vertical natural oil removal tank for coagulation, separation and
removal of oil, levitated sphere maze for removal of turbid by
microvortex, annular space for removal of dregs and the walnut shell
medium for filter and purification.

[0018] The detailed description of the technical plan of this invention is
shown below:

[0019] 1. Separation of Oil, Water and Impurity:

[0020] The reason why to decompose and treat the sump oil and acid oil
difficultly is that such oils are placed for long term in an open air
with the low light compositions and the water, heavy compositions and
sludge of the main compositions. The proportion of sump oil is close to
the water and the sump oil itself contains the asphaltine, colloid,
naphthenic acid and natural emulsifier enriched on the surface of the oil
and water to form the stable interfacial film. At the same time, acted by
the microorganism and acid liquor, the asphaltine, colloid and heavy
compositions in the sump oil degrades and gathers into a mass. Then the
added chemical agent is mixed with the natural emulsifier to make the
sump oil difficult to treat. Thus it becomes the multiple phase of crude
oil emulsion that small stable oil drops contain water and the water
contains the oil drops.

[0021] This invention firstly neutralizes and decomposes the residual acid
in the sump oil to make PH value maintains at a range of 6-8. After
decomposition of residual acid, the emulsifier in the sump oil is diluted
and transformed to lower the emulsification ability of the emulsifier,
reduce the trnsion of the oil sludge interface, break the balance of the
oil ion, and lower the surface strength of the drops so that it is easy
to gather into the larger drops.

[0022] After heating settlement, the sludge and water in the sump oil can
be dehydrated. Then the acid liquor in the acid oil of the sump oil is
decomposed so that PH value is neutral. Finally, the sump oil is fully
dehydrated under normal and reduced pressure. The study shows that the
proper electrolyte is added to increase the charging density of the
system at the time of emulsion breaking for the purpose of driving that
the oil is separated from the surface of the solid particles of the
sludge, so that they can replace the oil compositions and affix on the
surface of particles and disperse the particles and it creates better
conditions for oil removal from the solid particle surface.

[0023] In consideration of high viscosity of the sump oil, serious
emulsification, strong adhesive force of particles among solid, solid and
liquid and lower density difference, it is determined to adopt the
inversed emulsion breaking and electrochemical reaction driving, in
addition to the heating to achieve the purpose of removing the sludge and
water in the sump oil. The surface active agent and flocculating agent
are taken as the chemical agent. The role of the surface active agent is
to make the transition of the original emulsion that the water-in-oil
emulsion is converted to the oil-in-water emulsion. For that the
oil-in-water emulsion has poor stability, the water and sludge is easy to
settle; the flocculation refers to a process of coalescence of large
particles after stability loss of colloid and impurity (or absorption and
bridging of polymer substance). The role of the flocculating agent is to
develop the electrochemical reaction so that the colloid and impurity
contained in the sump oil after stability loss are formed to the larger
particles to remove the small impurities and sludge and develop the
emulsion breaking.

[0024] The emulsion splitter adopted in this invention is HF-01B special
sump oil emulsion spillter, which is the polycomponent non-ion surface
active agent generated after action of polyoxyethylene, fatty amidogen
ether and several base materials with the trunk chain of polyether
structure and with the terminal base containing hydroxy group, amino
group, ether group, carboxyl and poly hydrophilic functional groups. It
is a kind of agent with sound water solubility. In the sump oil, this
agent is added in proportion to lower the oil-water interfacial tension
of the sump oil, break the balance of electric potential, change the
organic oil soluble salt to water soluble salt, easily gather to large
drops. Finally, the compositions of the oil are separated for the purpose
of desalting, impurity removing, dehydration and emulsion breaking. The
technical indicators of HF-01 emulsion splitter are shown in Table 1 with
sound water solubility. When diluting, it is stirred slightly. Within
three minutes, it can be dissolved fully. The W/O sump oil with high acid
value, paraffin content, water content of 50% and strong hydroscopicity
to about 10%. The small quantity of the agent is used with no pollution
in a safe and reliable manner.

[0025] The commonly-used coagulating agents are aluminium sulphate,
ferrous sulfate, ferric trichloride, bodied ferric sulfate and inorganic
coagulating agent, polyacrylamide, propylene, 2-propylene 2-amine and
organic coagulating agent. This invention has a preference of HF-02
flocculating agent, which is a new high polymer flocculating agent with
the main composition of polyaluminium chloride (abbreviation of PAC),
chemical structural formula of [Al2(OH)nCl6-n]m, where,
1≦n≦5, m<10 is between AlCL3 and Al(OH)3. The bridging
polymerization is made by hydroxyl group. The molecular contains unequal
hydroxyl group with strong bridging absorption performance. During
hydrolysis, electrochemistry, agglomeration, settlement, absorption,
physical change and chemical change take place, characteristically of
that (1) the small quantity is used during coagulation; the flocculating
constituent is formed quickly; the settlement is made at a high speed;
the reaction settlement time is shortened and the treatment ability is
improved. (2) more flexible, pH more flexible than AL2(SO4)3 and
temperature more flexible than AL2(SO4)3; (3) 5-8 times as good as
aluminium sulphate and 3-5 times as good as ferric trichloride, better
than ferrous sulfate and alum; (4) no secondary basic accelerator, 30-70%
lower than low molecular flocculating agent on the cost; (5) quick
solution, low corrosion, removal of iron, manganese, arsenic, fluorine,
beryllium and chrome in the source water and good effects on removal of
radioactive contamination and organic coloring matter in the water. The
indicators are shown in Table 2.

[0026] For the said process, this invention adopts the method of air
floatation to quick up the chemical reaction, the emulsion breaking and
separation of compositions of the sump oil. The air floatation method is
an effective method to treat the high water-contained sump oil. The water
content in the sump oil of the oil field increases by above 50% and the
air floatation method is used to quick up the separation of the
compositions of the sump oil. It means that the high-pressure air is
introduced to the high-water sump oil to produce a great amount of the
tiny bubbles with an average diameter of 80 μm so that the petty oil
balls in the sump oil affix on the air bubbles. It floats on the water
surface with the air bubbles and it greatly quickens the process of
separation and the air bubbles produced by the air floatation play a role
of stirring, so that the added agent fully reacts with the sump oil. The
specialized stirring equipment is unnecessary, killing two birds with one
stone. After stirring and separation by way of air floatation method, the
settlement method is adopted to separate any sludge.

[0027] The basket-type filter is preferred in this invention and it is a
coarse filter to remove large impurities. The basket-type filter is a
kind of the advanced and practical filter with thick pipe, large quantity
of dirt collection, high pressure withstand, and easy installation and
cleaning. It is applicable for filter of large particles in oily water.
It is installed on the pipe to remove the large solid impurities in the
fluid, so that the production equipment is not blocked and work normally
to achieve the stability of process and safeguard the safe production.
The basket-type filter in this invention is made of stainless steel mesh
grid, characteristically of easy installation, removal, cleaning and
strong filter. The production experience shows that it is applicable to
remove the large particles of impurities in the sump oil and acid oil.

[0028] HF-B01-LCR LC oil pump is preferred as the oil pump for delivery of
sump oil in this invention. It is primarily used for delivery of sump oil
at the time of loading, unloading and emptying. This oil pump is improved
on the basis of HF-LC pump and it adopts the multi-sealing mode to ensure
that the oil pump does not leak if it works for long term. The flow rate
increases by 200 m3/h to meet the different requirements on flow during
production. The drive modes of HF-B01-LCR oil pump are flexible, with two
drive ways of reducer and belt. Meanwhile, this pump has low rotate
speed, effectively lowering the pulse vibration and noise, high
efficiency, saving energies; small in size, reducing the floor area. It
can be moved entirely during production, easy maintenance, counter
rotation. It has strong self-suction and easy operation without oil with
the suction length of 6 m. To deliver the high-viscosity medium, the pump
body is designed with the insulation cavity and it is heated with the
steam or conduction oil, to ensure the continuous or discontinuous work
of the oil pump and normal operation in the cold winter in northern area.

[0029] HF-B02-IMC stainless steel magnetic pump is preferred for delivery
of acid or alkali solution. It is a new product with the state-of-the-art
design after any drive pumps are integrated, primarily used for delivery
of acid or alkali solution during production. In accordance with ISO2858,
its flowed passage parts are made from the stainless steel. The
explosion-proof motor is used and it has sound corrosion resistance to
the organic acid, organic compound, alkaline solution, neutral solution
and other multiple gases. The double helix carbon graphite bearing is
well matched with the hard alloy bearing with strong wearing resistance
and service life. It is an ideal pump for leakproof delivery of corrosive
medium. It is single-stage single-way suction cantilever type. At the
time of delivery of high-temperature medium (the temperature of delivery
medium≦400° C.), the water cooler is not used, but the
intermediate coupler is installed. For the purpose of repair, the
circuits and motors are not disassembled but the intermediate coupler is
only disassembled. The specific parameters are as follows: the inlet
calibre of 80 mm, outlet calibre of 50 mm, flow of 50 m3/h, pump head of
80 m, motor power of 37 kw, motor speed of 2900 r/min, pressure of 1.6
mpa and temperature of -20° C.-400° C.

[0030] 2. Detergent Oil Dehydrating

[0031] After the residual acid, sludge and water in the oil are removed in
the said processes, the detergent oil meets the international standard,
but 10%-20% water is still retained. The structure of such water and oil
is stable, and it is difficult to separate in a chemical method. In this
invention, the physical method and the way of atmospheric and vacuum are
adopted to remove the remaining water in the oil. For that the boiling
point of the water is different from that of the oil, the water is fully
gasified at a temperature of 120° C. under atmospheric conditions.
However, the sump oil is placed in an open air for long term. The
distillation test shows that no light compositions of the sump oil are
shown before the temperature of 120° C. It also represents that
the light compositions of C1-C5 in the sump oil have been volatized.
Therefore, the co-boiling of water and oil is not produced. Under vacuum
station, the boiling point of water is reduced and it can be gasified at
low temperature.

[0032] The water-bearing oil in the oil cleaning tank is filtered by the
fine filter to remove the petty impurities. The test shows that, the
bag-type fine filter is most applicable to treatment of the fine filter
in the crude oil. HF-CO1 bag-type fine filter is preferred as the
bag-type fine filter with the precision of 1-1000 μm. The filter area
is 60% more than the standard filter bag in the same size. It is
characteristically of high passage, high filter precision, large filter
area, strong dirt collection, long replacement cycle of filter bag, sound
sealing, easy replacement of filter bag, easy and quick operation. It is
applicable to filter of any petty particles (less than 1000 ppm) for the
fluid with the precision range of 1-1000 μm and 1-1000 m3/h. HF-C01
bag-type fine filter is a easy, effective and commonly-used fluid filter
system, composed of container, bag and support. The detergent oil
filtered enters to the filter barrel under the pipeline pressure. After
electrolytic polishing for punching, it enters to the filter bag
supported by the filter basket to properly separate the solids and fluid
so that the detergent oil is fully filtered. Different filter precision
depends on the filter bag with different precision. For that the liquid
medium is flowed from the top end of the filter bag after the liquid
medium enters to the filter, so that the liquid can be evenly distributed
at the surface of filter of the whole filter bag and the distribution of
the fluid on the whole surface is constant. With less adverse effects of
the stirring motion, the solid matters in the liquid are retained in the
bag to obtain the clean fluid. The medium has characters of great
passage, pressure drop, easy operation and economical rationality.

[0033] After the impurities are removed from the detergent oil by fine
filter, it enters the heat exchanger for heat exchange and heating. The
hot fluid for heat exchange is from the international crude oil under
atmospheric and vacuum. HF-D01 shell-and-tube exchanger is preferred in
this invention. It is composed of shell, heat-transfer pipe bundle, tube
plate, traverse baffle (stop plate) as well as header. It is a dividing
wall type heat exchanger with the wall surface of pipe bundle enclosed in
the shell as the heat-transfer surface. It has simple structure and
reliable operation under high temperature and pressure. It is a
commonly-used type. The shell is columnar and the pipe bundles are
installed with both ends of the pipe bundles on the pipe plate. The cold
and hot fluids for heat exchange are flowed respectively inside and
outside the pipe. To improve the individual heat transfer coefficient of
the fluid outside the pipe, the numerous stop plates are installed in the
shell. The stop plate can improve the speed of fluid and drive the fluid
to conduct the transverse passage of pipe bundles for several times as
the specific routes and increase the turbulence extent of the fluid.

[0034] The temperature of detergent oil after heat exchange by the heat
exchanger reaches about 80° C., then it is heated to 120°
C. in the atmospheric tubular heater through the pump. The tubular heater
is composed of radiation chamber, convection chamber, funnel, waste heat
recovery system, burner and ventilation system, etc. The radiation
chamber is the core part of the heating furnace, as the hottest part in
the entire furnace. 70%-80% of the heat load of the entire furnace is
assumed by the radiation chamber. The convection chamber conducts the
heat exchange with the fume from the radiation chamber. In the convection
chamber, rows of furnace tubes are placed. These pipes are flushed by the
fume at a high speed for the purpose of effective heat exchange. The
chimney is a passage for fume exhaust. At the same time, control of the
discharge of fume is to control the combustion efficiency of the
radiation chamber, so as to control the temperature of the radiation
chamber, characteristically of high temperature (flame temperature of
1000-1600° C.), large heat transfer capacity (heat transfer
intensity of furnace pipe of 330000 kj/m2 h). The heating furnace takes
the natural gas in the oilfield or the coal gas produced from the coal
gas generator as the fuel to generate the high-temperature flame and
fume. With the furnace pipe wall, the crude oil flowed in the furnace
pipe is heated to meet the temperature needed.

[0035] After the detergent oil is heated to 120° C. in the
atmospheric heating furnace, it is dewatered in the atmospheric
dehydration tower. After the oil enters to the atmospheric tower, the
water molecule contained is vaporized immediately. The crude oil in the
tower flows to the tower bottom along the tower plate to the heat
exchanger for heat exchange of untreated detergent oil. In the
atmospheric tower, many tower plates are installed for the purpose of
heat transfer and medium transfer during dehydration and provision of
contact of gas and liquid. The tower plate makes the evenness of flow
from above to below, increases the contact area of steam and liquid,
lengthens the time of flow, fully removes the water in the crude oil.
After the atmospheric tower and heat exchanger, the detergent oil's
temperature falls to about 80° C. and its water-bearing rate falls
to about 5%. The next step is to realize the full dehydration after
vacuum tower.

[0036] After the detergent oil is dewatered in the atmospheric tower and
the heat exchange is made in the heat exchanger, its pressure keeps
between 0.2-0.3 MPa. After it is delivered to the vacuum tower by the oil
pump, the pressure is reduced till full dehydration in principle that the
boiling point reduces when the pressure of the liquid is lower than under
atmospheric conditions. At the top of the vacuum tower, the vacuum
compressor is installed for suction to keep the vacuum of the flash tower
at about 20-70 kPa. After the detergent oil at a temperature of
80° C. enters to the vacuum tower, the oil will boil immediately
under vacuum of the tower, and the water molecule is gasified to be the
water vapor and it is suctioned to the vacuum tower by the vacuum
compressor at the top of the tower. The pressure increases to 0.2-0.3 MPa
by the compressor, then it is condensed to the water at a temperature of
40° C. by the condenser, and it is delivered to the water storage
tank for further purification. For that the vacuum dehydration tower
works under vacuum, the tower bottom is uplifted to the proper height so
that the crude oil at the tower bottom is pumped out by the oil pump
successfully. The oil pump is located at the tower bottom as close as
possible, to lower the resistance loss of source pipes. The position
difference between the tower bottom liquid level and pump entry depends
on the vacuum, generally 5-10 m. The temperature of international crude
oil after full dehydration in the vacuum tower falls to 60°
C.-70° C. It is directly delivered to the oil tank for storage
without heat exchange.

[0037] The cleaned water has the water-bearing rate less than 0.2% after
the dehydration by the said atmospheric and vacuum dehydration system. It
can be directly transferred to the refinery until all indicators after
test fully meet the standards of the international crude oil.

[0038] 3. Sewage Purification

[0039] A little sump oil and some suspended impurities are contained in
the sewage that sump oil decomposition produces, and in the condensation
water that detergent oil under the normal/reduced pressure produces. Such
a sewage will directly pollute water source and stratum if it is
discharged or flooded underground. So it must be clarified to reach the
standard.

[0040] For this invention, the sewage concerned is input to vertical oil
removal tank. With gravity separation method, oil and water are separated
by their density difference. The sewage in the tank stays for 3 hours,
with dropping flow rate 0.5-0.8 mm/s, inflow water oil content 1000 mg/L,
effluent oil content less than 200 mg/L, and oil removal efficiency 80%.
For inflow suspended matter 300 mg/L, effluent suspended matter is less
than 240 mg/L, and suspension removal rate of 20%. In this way, the
sewage with larger particles and floating sewage after being stilled, so
that continuous phase oil slick can surface. When surface oil is thick,
suction pump can be applied to transfer it to sewage tank for
re-purification. The sediment is drained to kettle by outlet at bottom of
the tank for chemical thermal washing with aqueous alkali, solidified
with other sewage at last.

[0041] The sewage being purified by vertical tank has very low oil content
rate and impurity rate, so it's not necessary to gradually clarify it
with other complicated methods. Filtering it in oil-water filter can
completely remove the sewage and all impurity in water, so that the
sewage can reach national standard for purified water.

[0042] HF-E01 oil filter is selected, consisted by filtering tank of thick
and thin two levels based on coagulation dynamics and micro-vortex
principles. Pressurized by lift pump, the sewage enters thick filtration
tank for oil removal. The treated sewage flows in micro-suspension
enclosure for purification with micro-vortex, then in ring space for
gravity settling and slag separation. After that, the water flows in
filter cartridge sidewise, with fine particle and oil droplets retained
by filter medium nutshell. The designed removal rate for oil and
suspension is more than 80%. The sump oil separated outflows from upper
oil tube, and impurities are discharged from lower blow-off pipe. Being
filtered, the water is drained from center outlet pipework. Flowing in,
filtering and discharging is operated simultaneously. For conventional
wastewater or sewage, washing desorption can achieve the same desired
effect. This device carries the advantage of water treatment equipments
in domestic and abroad, integrating vortex coagulation separation with
micro vortex decontamination, levitated sphere oil removing, walnut shell
filtration and purification, filtering media filling by pump, and cycle
medium washing and regeneration etc. The device is multifunctional and
multi-level, separating oil and water while isolating liquid and solid,
featured by high capacity, high filtration precision, continuous
discharge of sewage and oil, easy regeneration, simple operation, and
safe reliable running etc. For detailed data, see Table 3. Being tested,
the sewage filtered by this device completely complies with the standard
specified in Recommended Indicators and Analysis Methods for Water
Quality of Clastic Rocks Oil Deposit SY-T5329-94, and GB8978-88 national
comprehensive standard on exterior drainage. Standardized, the water can
be directly discharged or flooded underground.

[0043] 4. Sludge Solidification

[0044] Sediment impurities from the said process contain about 15% crude
oil through the chemical laboratory analysis, which is separated with the
chemical thermal washing method. This method can decrease oil residual
rate to less than 0.5%. The recycled alkali can be used repeatedly,
conforming to national environmental requirement.

[0045] Being analyzed, the sludge chemically washed contains less than
0.5% residual oil, and about 40% water. The mineral components of the
sludge: 95% calcite, 1% anhydrite, 1% quartz, 2% rock salt and 1% potash
feldspar. Measured by wet sieving device, the grain diameter of mud
particle is between 180-200 meshes. For this invention, cement based
solidifying, quicklime and alumina coagulant aid method can be applied to
make final consolidation. 425#common silicate cement whose ingredients
are dicalcium silicate and tricalcium silicate is appled in the curing
agent to make a hydration reaction after mixing with sludge to form
hydraulic materials, mainly including tobermorite and ettringite, to be
up to the effect of sludge consolidation. At the same time, hydration
products can stabilize and seal pollutants to reduce environment
pollution. Coagulant aid contains calcined lime and alumina, which have
hydration reaction with cement during consolidation process, reduce
cement volume, promote coagulation, enhance intensity of curing block,
and increase the absorption of harmful substances. Quicklime and alumina
produce hydration reaction with cement, generating calcium hydroxide,
aluminum hydroxide and other non-water-soluble substances that can absorb
and precipitate a large number of heavy metals and other toxic hazardous
substances and reduce leaching rate of hazardous substances so as to
detoxify. Quick lime can also be used to sterilize for sludge for better
hazard-free treatment.

[0046] For the new method of final solidification treatment, cement-based
solidification, quick lime and alumina coagulant aid have the following
advantages: (1) during sludge treatment process, less curing agent and
coagulant aid is used for better solidification effect, lowering sludge
volume after solidified, sterilize pathogenic bacteria and parasite
(ovum) in sludge; (2) being solidified, it can avoid the loss of harmful
substance in heavy metals to prevent secondary pollution; (3) the
solidified sludge changes mobility, with low volume, high compression
resisting strength and immersion resisting capability, and lower leaching
toxicity, maintaining solid formation and stable chemical properties for
long-term, keeping good stability after being soaked in water, acid and
alkali while the heavy metals in sludge will be reserved to weaken
mosquitoes-prone environment; (4) the solidified sludge can be used as
road material, building materials, or landfill cover soil, which improves
its economic value and realizes resource utilization.

[0047] The beneficial effects of this invention are as follows:

[0048] 1. The waste oil and acid oil centralized processing solves the
problem of difficult separation of oil, water and impurities in waste oil
and acid oil. After the centralized processing, there is no sewage,
sludge and sewage oil discharge, which substantially reduces the
pollution to surrounding environment and corrosion to equipment. Oil tank
is kept clean for long-term, without being desilted, which reduces the
expense on cleaning and staffing.

[0049] 2. The centralized processing turns waste into wealth, recycling a
large number of crude oil, reducing production cost of crude oil. The
solidified sludge can also be directly used as building materials.

[0050] 3. The invention greatly enhances economic benefits of oil field.
The waste oil and acid oil being processed reaches national standard. The
recycled GB crude oil account for more than 70% of waste oil. By current
list price of GB crude oil, it can increase income for tens of millions
Yuan each year, and enhance crude oil production.

[0051] Other advantages, objectives and features of this invention will be
explained in the following specifications to some extent, which are
obvious for the technical staff in this domain based on the following
study, or presented in the practice of this invention. The object and
other advantages of this product can be realized and obtained by the
following instruction book, claim of right and the structure specially
pointed out in figure.

[0056] With the following figures, the preference examples are described
in detail.

Example 1

[0057] X-ray diffractometer analyzes that in the waste oil and acid oil of
Jidong Oilfield, the content of large particle impurity is about 1%-2%.
Fine sediment and other impurities account for about 15%-20%, water
content 50%-60%, and pure oil 20-30%. Basket-type filter is used to
initially filter sediment impurities of larger volume. The waste oil
filtered is poured into kettle for separation of silt, oil and water.
Compressed air is injected from the coiler of hole diameter 80 μm at
the bottom of kettle, generating fine bubble of diameter about 80 μm
for mixture. Add 10% thickness sodium carbonate solution in waste oil to
stabilize PH value at 7.2, then put in PR-02 demulsifier of 0.6% of waste
oil volume in the tank, and flocculant PFS to react continuously. The
lasting time of injecting compressed air is 3 hours. Then stop injecting,
still to precipitate for 5 hours, input the purification oil at upper
kettle to purification tank, the sewage at middle is discharged in
caustic tank while upper sludge is left in kettle.

Example 2

[0058] Basket-type filter is used to initially filter sediment impurities
with a larger volume. The waste oil filtered is poured into kettle by
"HF-B01-LCR lobe oil pump. When the oil in kettle is heated to 60°
C., compressed air is injected from the coiler of hole diameter 90 μm
at the bottom of kettle, generating fine bubble of diameter about 90
μm for mixture. Add 15% thickness sodium carbonate solution in waste
oil to stabilize PH value at 7.5. When the temperature in kettle is
increased to 80° C., add PR-02 demulsifier of 0.7% of waste oil
volume in the kettle, and HF-02 type flocculant of 0.4% of waste oil
volume in the kettle. The lasting time of injecting compressed air is 3.5
hours. Then stop injecting, still to precipitate for 6 hours, input the
purification oil at upper kettle to purification tank, the sewage at
middle is discharged in caustic tank while upper sludge is left in
kettle.

[0059] Basket-type filter is used to filter waste oil. The waste oil
filtered is poured into kettle by "HF-B01-LCR lobe oil pump. When the oil
in kettle is heated to 50° C., compressed air is injected from the
coiler of hole diameter 60 μm at the bottom of kettle, generating fine
bubble of diameter about 60 μm for mixture. Add 7% thickness sodium
carbonate solution in waste oil with HF-B02-IMC stainless steel magnetic
clutch to stabilize PH value at 6.0. When the temperature in kettle is
increased to 70° C., add HF-01B demulsifier of 0.8% of waste oil
volume in the kettle, and HF-02 type flocculant of 0.2% of waste oil
volume in the kettle. The lasting time of injecting compressed air is 2.5
hours. Then stop injecting, still to precipitate for 6 hours, input the
purification oil at upper kettle to purification tank, the sewage at
middle is discharged in caustic tank while upper sludge is left in
kettle.

Example 4

[0060] The implementation method is basically the same with Example 1. The
difference is that the purified oil in the tank is filtered by HF-C01
bag-type fine filter of bore diameter 1000 μm, heated to 120°
C., dehydrated in the dehydration tower, heated to 80° C. by heat
exchanger, put in the vacuum dehydration tower to be dehydrated at 70 kPa
for GB crude oil. The water vapor extracted from the said
atmospheric/vacuum dehydration tower forms sewage after condensed, and
then enters the sewage tank.

Example 5

[0061] The implementation method is basically the same with Example 1. The
difference is that the sewage in the tank is discharged in vertical
natural oil removal tank, with falling speed 0.7 mm/s. Being filtered by
HF-E01 oil filter, the effluent is used for underground flooding.

[0062] Being tested, the sewage filtered by this device completely
complies with the standard specified in recommended indicators and
analysis methods for water quality of clastic rocks oil deposit
SY-T5329-94, and GB8978-88 national comprehensive standard on exterior
drainage. Standardized, the water can be directly discharged.

Example 6

[0063] The implementation method is basically the same with Example 1. The
difference is that the 15% sodium hydroxide aqueous solution at
70° C. is washed for 20 min by solid-to-liquid ratio 2:1, and then
precipitated for 3 hours. The clarified oil washed from upper surface is
put in clarified oil tank. The alkali liquor at middle-level is recycled
in alkali tank. Silt impurities at the bottom of kettle are transferred
in mud solidifying pool with mud pump.

Example 7

[0064] The implementation method is basically the same with Example 6. The
difference is that based on the mud weight in solidifying pool, add 8%
silicate cement, 3% quick lime and 1% alumina, which is mixed evenly with
mechanical mixer and maintained for 15 days to form the solidified sludge
of compressive strength 4380 KN/m2 for road construction and building
materials.

[0065] For reference to some optimized examples clearly specified in this
invention, the ordinary technicians in this field should understand that
it can be changed in various forms and details, without deviating from
the spirit and scope defined by claim of right.